From: Joshua Slive Date: Tue, 26 Feb 2002 19:02:35 +0000 (+0000) Subject: Commit the transformations from the xml docs. X-Git-Tag: 2.0.33~130 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5cd209cc3902298588ce22268c4fcb17b9b7a372;p=apache Commit the transformations from the xml docs. git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93580 13f79535-47bb-0310-9956-ffa450edef68 --- diff --git a/docs/manual/mod/mpm_common.html b/docs/manual/mod/mpm_common.html index 8bb64f2de3..5ad70b1948 100644 --- a/docs/manual/mod/mpm_common.html +++ b/docs/manual/mod/mpm_common.html @@ -1,696 +1,1165 @@ - - - - - - - Apache MPM Common Directives - - - - - - -

Multi-Processing Module Common - Directives

- -

This file documents directives that are implemented by more - than one multi-processing module (MPM).

- -

Directives

- - -
- -

CoreDumpDirectory directive

- - -

Syntax: CoreDumpDirectory - directory
- Default: the same location as - ServerRoot
- Context: server config
- Status: MPM
- Module: worker, perchild, - prefork, mpm_winnt

- -

This controls the directory to which Apache attempts to - switch before dumping core. The default is in the ServerRoot directory, however + + + + +mpm_common - Apache HTTP Server + + + +

+
+[APACHE DOCUMENTATION]

Apache HTTP Server Version 2.0

+
+

Apache Module mpm_common

+ + + + +
+ + + + + + + +
Description: +A collection of directives that are implemented by +more than one multi-processing module (MPM) +
Status:MPM
+
+

Directives

+ +
+

+CoreDumpDirectory Directive +

+ + + + +
+ + + + + + + + + + + + + + + + + + + +
Description: Sets the directory where Apache attempts to +switch before dumping core
Syntax: +CoreDumpDirectory directory + +
Default:CoreDumpDirectory ServerRoot
Context:server config
Status:MPM
Module:worker, perchild, prefork, mpm_winnt
+
+ + + +

This controls the directory to which Apache attempts to + switch before dumping core. The default is in the + ServerRoot directory, however since this should not be writable by the user the server runs as, core dumps won't normally get written. If you want a core dump for debugging, you can use this directive to place it in a different location.

-
- -

Group directive

- - -

Syntax: Group - unix-group
- Default: Group - #-1
- Context: server config, virtual - host
- Status: MPM
- Module: worker, perchild, - prefork

- The Group directive sets the group under which the server will - answer requests. In order to use this directive, the - stand-alone server must be run initially as root. - Unix-group is one of: - -
-
A group name
- -
Refers to the given group by name.
- -
# followed by a group number.
- -
Refers to a group by its number.
-
- It is recommended that you set up a new group specifically for + + +
+

+Group Directive +

+ + + + +
+ + + + + + + + + + + + + + + + + + + +
Description: Sets the group under which the server will answer +requests
Syntax: +Group unix-group + +
Default:Group #-1
Context:server config, virtual host
Status:MPM
Module:worker, perchild, prefork
+
+ + +

The Group directive sets the group under + which the server will answer requests. In order to use this + directive, the stand-alone server must be run initially as root. + Unix-group is one of:

+ + +
+ +
A group name
+ + +
Refers to the given group by name.
+ + +
# followed by a group number.
+ + +
Refers to a group by its number.
+ +
+ +

It is recommended that you set up a new group specifically for running the server. Some admins use user nobody, - but this is not always possible or desirable. + but this is not always possible or desirable.

-

Note: if you start the server as a non-root user, it will + +

Note: if you start the server as a non-root user, it will fail to change to the specified group, and will instead continue to run as the group of the original user.

-

Special note: Use of this directive in <VirtualHost< - is no longer supported. To implement the suEXEC wrapper with Apache 2.0, use - the SuexecUserGroup - directive. SECURITY: See User for a - discussion of the security considerations.

-
- -

PidFile directive

- - -

Syntax: PidFile - filename
- Default: PidFile - logs/httpd.pid
- Context: server config
- Status: MPM
- Module: worker, perchild, - prefork, mpm_winnt

- -

The PidFile directive sets the file to which the server - records the process id of the daemon. If the filename does not - begin with a slash (/) then it is assumed to be relative to the - ServerRoot.

- -

It is often useful to be able to send the server a signal, - so that it closes and then reopens its ErrorLog and TransferLog, and - re-reads its configuration files. This is done by sending a - SIGHUP (kill -1) signal to the process id listed in the - PidFile.

- -

The PidFile is subject to the same warnings about log file - placement and security.

-
- -

Listen directive

- -

Syntax: Listen - [IP-address:]port number
- Context: server config
- Status: MPM
- Module: worker, perchild, - prefork, mpm_winnt

- -

The Listen directive instructs Apache to listen to only - specific IP addresses or ports; by default it responds to - requests on all IP interfaces. The Listen directive is now - a required directive. If it is not in the config file, the - server will fail to start. This is a change from previous - versions of Apache. - -

The Listen directive tells the server to accept incoming + +

Special note: Use of this directive in <VirtualHost< is + no longer supported. To implement the suEXEC wrapper with Apache 2.0, use the + SuexecUserGroup + directive. SECURITY: See User for a discussion of the + security considerations.

+ + +
+

+Listen Directive +

+ + + + +
+ + + + + + + + + + + + + + + + +
Description: Sets the IP addresses and ports that the server +listens to
Syntax: +Listen [IP-address:]portnumber + +
Context:server config
Status:MPM
Module:worker, perchild, prefork, mpm_winnt
+
+ + +

The Listen directive instructs Apache to + listen to only specific IP addresses or ports; by default it + responds to requests on all IP interfaces. The Listen directive is + now a required directive. If it is not in the config file, the + server will fail to start. This is a change from previous versions + of Apache.

+ + +

The Listen directive tells the server to accept incoming requests on the specified port or address-and-port combination. If only a port number is specified, the server listens to the given port on all interfaces. If an IP address is given as well as a port, the server will listen on the given port and interface.

-

Multiple Listen directives may be used to specify a number + +

Multiple Listen directives may be used to specify a number of addresses and ports to listen to. The server will respond to requests from any of the listed addresses and ports.

-

For example, to make the server accept connections on both + +

For example, to make the server accept connections on both port 80 and port 8000, use:

-
-   Listen 80
+
+

+
+
+
+
+

+   Listen 80

    Listen 8000
-
+

+

     To make the server accept connections on two specified
     interfaces and port numbers, use 
-
-   Listen 192.170.2.1:80
+

+
+
+
+
+

+   Listen 192.170.2.1:80

    Listen 192.170.2.5:8000
-
+

+

     IPv6 addresses must be surrounded in square brackets, as in the
     following example:
-
+

+
+
+
+
+

    Listen [fe80::a00:20ff:fea7:ccea]:80
-
-
-    
See Also: DNS
-    Issues

-     See Also: Setting
-    which addresses and ports Apache uses

-     See Also: Known
-    Bugs

-    

-
-    
ListenBacklog
-    directive

-
-    
Syntax: ListenBacklog
-    backlog

-     Default: ListenBacklog
-    511

-     Context: server config

-     Status: MPM

-     Module: worker, perchild,
-    prefork, mpm_winnt

-
-    
The maximum length of the queue of pending connections.
+

+

+
+
+

+See also:
+

+
+

+

+ListenBackLog Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Maximum length of the queue of pending connections
Syntax:
+ListenBacklog backlog
+
+
Default:ListenBacklog 511
Context:server config
Status:MPM
Module:worker, perchild, prefork, mpm_winnt

+

+
+    
+
The maximum length of the queue of pending connections.
     Generally no tuning is needed or desired, however on some
     systems it is desirable to increase this when under a TCP SYN
     flood attack. See the backlog parameter to the
     listen(2) system call.

 
-    
This will often be limited to a smaller number by the
+    
+
This will often be limited to a smaller number by the
     operating system. This varies from OS to OS. Also note that
     many OSes do not use exactly what is specified as the backlog,
     but use a number based on (but normally larger than) what is
     set.

-    

-
-    
LockFile
-    directive

-
-    
Syntax: LockFile
-    filename

-     Default: LockFile
-    logs/accept.lock

-     Context: server config

-     Status: MPM

-     Module: worker, perchild,
-    prefork

-
-    
The LockFile directive sets the path to the lockfile used
-    when Apache is compiled with either USE_FCNTL_SERIALIZED_ACCEPT
-    or USE_FLOCK_SERIALIZED_ACCEPT. This directive should normally
-    be left at its default value. The main reason for changing it
-    is if the logs directory is NFS mounted, since
-    the lockfile must be stored on a local disk.
-    The PID of the main server process is automatically appended to
-    the filename.

-
-    
SECURITY: It is best to avoid putting this
+
+
+

+

+LockFile Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Location of the accept serialization lock file
Syntax:
+LockFile filename
+
+
Default:LockFile logs/accept.lock
Context:server config
Status:MPM
Module:worker, perchild, prefork

+

+
+    
+
The LockFile directive sets the path to
+    the lockfile used when Apache is compiled with either
+    USE_FCNTL_SERIALIZED_ACCEPT or USE_FLOCK_SERIALIZED_ACCEPT. This
+    directive should normally be left at its default value. The main
+    reason for changing it is if the logs directory is
+    NFS mounted, since the lockfile must be stored on a local
+    disk.  The PID of the main server process is
+    automatically appended to the filename.

+
+    
+

+SECURITY: It is best to avoid putting this
     file in a world writable directory such as
     /var/tmp because someone could create a denial of
     service attack and prevent the server from starting by creating
     a lockfile with the same name as the one the server will try to
     create.

-    

-
-    
MaxClients
-    directive

-    
-
-    
Syntax: MaxClients
-    number

-     Default: MaxClients
-    8 (with threads) MaxClients 256 (no
-    threads)

-     Context: server config

-     Status: MPM

-     Module: worker, prefork

-
-    
The MaxClients directive sets the limit on the number of
-    child processes that will be created to serve requests. When
-    the server is built without threading, no more than this number
-    of clients can be served simultaneously. To configure more than
-    256 clients with the prefork MPM, you must use the ServerLimit directive.  To configure
-    more than 1024 clients with the worker MPM, you must use the
-    ServerLimit and ThreadLimit directives.
-
-    
Any connection attempts over the MaxClients limit will
-    normally be queued, up to a number based on the ListenBacklog directive. Once a child
-    process is freed at the end of a different request, the
-    connection will then be serviced.

-
-    
When the server is compiled with threading, then the maximum
+
+
+

+

+MaxClients Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Maximum number of child processes that will be created
+to serve requests
Syntax:
+MaxClients number
+
+
Default:>MaxClients
+    8 (with threads) MaxClients 256
Context:server config
Status:MPM
Module:worker, prefork

+

+
+    
+
The MaxClients directive sets the limit
+    on the number of child processes that will be created to serve
+    requests. When the server is built without threading, no more than
+    this number of clients can be served simultaneously. To configure
+    more than 256 clients with the prefork MPM, you must use the
+    ServerLimit directive.
+    To configure more than 1024 clients with the worker MPM, you must
+    use the ServerLimit and
+    ThreadLimit directives.

+
+    
+
Any connection attempts over the
+    MaxClients limit will normally be queued,
+    up to a number based on the ListenBacklog directive. Once a child
+    process is freed at the end of a different request, the connection
+    will then be serviced.

+
+    
+
When the server is compiled with threading, then the maximum
     number of simultaneous requests that can be served is obtained
-    from the value of this directive multiplied by ThreadsPerChild.

-    

-
-    
MaxRequestsPerChild
-    directive

-    
-
-    
Syntax: MaxRequestsPerChild
-    number

-     Default:
-    MaxRequestsPerChild 10000

-     Context: server config

-     Status: MPM

-     Module: worker, prefork,
-    perchild, mpm_winnt

-
-    
The MaxRequestsPerChild directive sets the limit on the
-    number of requests that an individual child server process will
-    handle. After MaxRequestsPerChild requests, the child process
-    will die. If MaxRequestsPerChild is 0, then the process will
-    never expire.

-
-    
Setting MaxRequestsPerChild to a non-zero limit has two
-    beneficial effects:

-
-    
    
-      
  • it limits the amount of memory that process can consume
+    from the value of this directive multiplied by
+    ThreadsPerChild.
    
+
+
+
    
+
    
+MaxRequestPerChild Directive
+
    
+
+
+
+
+
    
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
    Description: Limit on the number of requests that an individual child server
+will handle during its life
    Syntax:
+MaxRequestsPerChild number
+
+
    Default:MaxRequestsPerChild 10000
    Context:server config
    Status:MPM
    Module:worker, perchild, prefork, mpm_winnt
    
+
    
+
+    
+
    The MaxRequestsPerChild directive sets
+    the limit on the number of requests that an individual child
+    server process will handle. After
+    MaxRequestsPerChild requests, the child
+    process will die. If MaxRequestsPerChild is
+    0, then the process will never expire.
    
+
+    
+
    Setting MaxRequestsPerChild to a
+    non-zero limit has two beneficial effects:
    
+
+    
+
      
+      
+
    • it limits the amount of memory that process can consume
       by (accidental) memory leakage;
      • 
 
-      
    • by giving processes a finite lifetime, it helps reduce
+      
+
    • by giving processes a finite lifetime, it helps reduce
       the number of processes when the server load reduces.
      • 
-    
    
+    
+

 
-    
NOTE: For KeepAlive requests, only
+    
+

+NOTE: For KeepAlive requests, only
     the first request is counted towards this limit. In effect, it
     changes the behavior to limit the number of
     connections per child.

-    

-
-    
MaxSpareThreads directive

-
-    
Syntax: MaxSpareThreads
-    number

-     Default: MaxSpareThreads
-    10 (Perchild) or 500 (worker)

-     Context: server config

-     Status: core

-     Module: worker, perchild

-
-    
Maximum number of idle threads. Different MPMs deal with
-    this directive differently. Perchild monitors the number of idle
-    threads on a per-child basis. If there are too many idle
-    threads in that child, the server will begin to kill threads
+
+
+

+

+MaxSpareThreads Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Maximum number of idle threads
Syntax:
+MaxSpareThreads number
+
+
Default:MaxSpareThreads 10 (Perchild) or 500 (worker)
Context:server config
Status:MPM
Module:worker, perchild

+

+
+    
+
Maximum number of idle threads. Different MPMs deal with this
+    directive differently. perchild monitors the
+    number of idle threads on a per-child basis. If there are too many
+    idle threads in that child, the server will begin to kill threads
     within that child.

 
-    
worker deals with idle threads on a server-wide basis. If
-    there are too many idle threads in the server then child
-    processes are killed until the number of idle threads is less
-    than this number.

-
-    
See also MinSpareThreads and
-    StartServers.

-    

-
-    
MaxThreadsPerChild directive

-
-    
Syntax: MaxThreadsPerChild
-    number

-     Default:
-    MaxThreadsPerChild 64 Context: server config

-     Status: core

-     Module: worker, perchild

-
-    
Maximum number of threads per child. For MPMs with a
+    
+

+worker deals with idle threads on a
+    server-wide basis. If there are too many idle threads in the
+    server then child processes are killed until the number of idle
+    threads is less than this number.

+
+
+
+

+See also:
+

+
+

+

+MaxThreadsPerChild Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Maximum number of threads per child process
Syntax:
+MaxThreadsPerChild number
+
+
Default:MaxThreadsPerChild 64
Context:server config
Status:MPM
Module:worker, perchild

+

+
+    
+
Maximum number of threads per child. For MPMs with a
     variable number of threads per child, this directive sets the
     maximum number of threads that will be created in each child
     process. To increase this value beyond its default, it is
     necessary to change the value of the compile-time define
     HARD_THREAD_LIMIT and recompile the server.

-    

-
-    
MinSpareThreads directive

-    
-
-    
Syntax: MinSpareServers
-    number

-     Default: MaxSpareThreads
-    5 (Perchild) or 250 (worker)

-     Context: server config

-     Status: core

-     Module: worker, perchild

-
-    
Minimum number of idle threads to handle request spikes.
-    Different MPMs deal with this directive differently. Perchild
-    monitors the number of idle threads on a per-child basis. If
-    there aren't enough idle threads in that child, the server will
-    begin to create new threads within that child.

-
-    
worker deals with idle threads on a server-wide basis. If
-    there aren't enough idle threads in the server then child
-    processes are created until the number of idle threads is
-    greater than number.

-    See also MaxSpareThreads and StartServers. 
-    

-
-    
NumServers
-    directive

-
-    
Syntax: NumServers
-    number

-     Default: NumServers
-    2

-     Context: server config

-     Status: MPM

-     Module: perchild

-
-    
Number of children alive at the same time. MPMs that use
+
+
+

+

+MinSpareThreads Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Minimum number of idle threads available to handle request
+spikes
Syntax:
+MinSpareServers number
+
+
Default:MinSpareThreads 5 (Perchild) or 250 (worker)
Context:server config
Status:MPM
Module:worker, perchild

+

+
+    
+
Minimum number of idle threads to handle request spikes.
+    Different MPMs deal with this directive
+    differently. perchild monitors the number of idle
+    threads on a per-child basis. If there aren't enough idle threads
+    in that child, the server will begin to create new threads within
+    that child.

+
+    
+

+worker deals with idle threads on a
+    server-wide basis. If there aren't enough idle threads in the
+    server then child processes are created until the number of idle
+    threads is greater than number.

+
+
+

+See also:
+

+
+

+

+NumServers Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Total number of children alive at the same time
Syntax:
+NumServers number
+
+
Default:NumServers 2
Context:server config
Status:MPM
Module:perchild

+

+
+    
+
Number of children alive at the same time. MPMs that use
     this directive do not dynamically create new child processes so
     this number should be large enough to handle the requests for
     the entire site.

-    

-
-    
ScoreBoardFile
-    directive

-    
-
-    
Syntax: ScoreBoardFile
-    filename

-     Default: ScoreBoardFile
-    logs/apache_status

-     Context: server config

-     Status: MPM

-      Module: worker, perchild,
-    prefork

-
-    
The ScoreBoardFile directive is required on some
-    architectures to place a file that the server will use to
-    communicate between its children and the parent. The easiest
-    way to find out if your architecture requires a scoreboard file
-    is to run Apache and see if it creates the file named by the
-    directive. If your architecture requires it then you must
-    ensure that this file is not used at the same time by more than
-    one invocation of Apache.

-
-    
If you have to use a ScoreBoardFile then you may see
-    improved speed by placing it on a RAM disk. But be careful that
-    you heed the same warnings about log file placement and security.

-
-    
See Also: Stopping and Restarting Apache

-    

-
-    
SendBufferSize
-    directive

-    
-
-    
Syntax: SendBufferSize
-    bytes

-     Context: server config

-     Status: MPM

-     Module: worker, perchild,
-    prefork, mpm_winnt

-    The server will set the TCP buffer size to the number of bytes
+
+
+

+

+PidFile Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Sets the file where the server records the process ID
+of the daemon
Syntax:
+PidFile filename
+
+
Default:PidFile logs/httpd.pid
Context:server config
Status:MPM
Module:worker, perchilde, prefork, mpm_winnt

+

+
+    
+
The PidFile directive sets the file to
+    which the server records the process id of the daemon. If the
+    filename does not begin with a slash (/) then it is assumed to be
+    relative to the ServerRoot.

+
+    
+
It is often useful to be able to send the server a signal,
+    so that it closes and then reopens its ErrorLog and TransferLog, and
+    re-reads its configuration files. This is done by sending a
+    SIGHUP (kill -1) signal to the process id listed in the
+    PidFile.

+
+    
+
The PidFile is subject to the same warnings about log file
+    placement and security.

+
+
+

+

+ScoreBoardFile Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Location of the file used to store coordination data for
+the child processes
Syntax:
+ScoreBoardFile file-path
+
+
Default:ScoreBoardFile logs/apache_status
Context:server config
Status:MPM
Module:worker, perchild, prefork

+

+
+    
+
The ScoreBoardFile directive is required
+    on some architectures to place a file that the server will use to
+    communicate between its children and the parent. The easiest way
+    to find out if your architecture requires a scoreboard file is to
+    run Apache and see if it creates the file named by the
+    directive. If your architecture requires it then you must ensure
+    that this file is not used at the same time by more than one
+    invocation of Apache.

+
+    
+
If you have to use a ScoreBoardFile then
+    you may see improved speed by placing it on a RAM disk. But be
+    careful that you heed the same warnings about log file placement
+    and security.

+
+
+

+See also:
+

+
+

+

+SendBufferSize Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: TCP buffer size
Syntax:
+SendBufferSize bytes
+
+
Context:server config
Status:MPM
Module:worker, perchild, prefork, mpm_winnt

+

+
+    
+
The server will set the TCP buffer size to the number of bytes
     specified. Very useful to increase past standard OS defaults on
     high speed high latency (i.e., 100ms or so, such as
-    transcontinental fast pipes) 
-    

-
-    
ServerLimit

-
-    
Syntax: ServerLimit
-    number

-     Default: ServerLimit
-    256 (prefork MPM), ServerLimit 16 (worker MPM)

-     Context: server config

-     Status: MPM

-     Module: prefork, worker

-
-    
For the prefork MPM, this directive sets the maximum configured 
-    value for MaxClients for
-    the lifetime of the Apache process.  For the worker MPM, this 
-    directive in combination with 
-    ThreadLimit sets the maximum configured value for
-    MaxClients
-    for the lifetime of the Apache process.  Any attempts to change 
-    this directive during a restart will be ignored, but
-    MaxClients can be modified during a restart.

-
-    
Special care must be taken when using this directive.
-    If ServerLimit is set to a value much higher than
-    necessary, extra, unused shared memory will be allocated.
-    If both ServerLimit and MaxClients 
-    are set to values higher than the system can handle, Apache 
-    may not start or the system may become unstable.

-
-    
With the prefork MPM, use this directive only if you need to 
-    set MaxClients higher higher than 256.  Do not set 
-    the value of this directive any higher than what you might want 
-    to set MaxClients to.

-
-    
With the worker MPM, use this directive only if your 
-    MaxClients and ThreadsPerChild 
-    settings require more than 16 server processes.  Do not set the 
-    value of this directive any higher than the number of server 
-    processes required by what you may want for MaxClients
-     and ThreadsPerChild.

-    

-
-    
StartServers
-    directive

-    
-
-    
Syntax: StartServers
-    number

-     Default: StartServers
-    5

-     Context: server config

-     Status: MPM

-     Module: worker, prefork

-
-    
The StartServers directive sets the number of child server
-    processes created on startup. As the number of processes is
-    dynamically controlled depending on the load, there is usually
-    little reason to adjust this parameter.

-
-    
See also MinSpareThreads and
-    MaxSpareThreads.

-    

-
-    
StartThreads
-    directive

-
-    
Syntax: StartThreads
-    number

-     Default: StartThreads
-    5

-     Context: server config

-     Status: MPM

-     Module: perchild

-
-    
Number of threads each child creates on startup. As the
+    transcontinental fast pipes).

+
+
+

+

+ServerLimit Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Upper limit on configurable number of processes
Syntax:
+ServerLimit number
+
+
Default:ServerLimit 256 (prefork), ServerLimit 16 (worker)
Context:server config
Status:MPM
Module:worker, prefork

+

+
+    
+
For the prefork MPM, this directive sets the
+    maximum configured value for MaxClients for the lifetime of the
+    Apache process.  For the worker MPM, this directive in combination
+    with ThreadLimit sets
+    the maximum configured value for MaxClients for the lifetime of the
+    Apache process.  Any attempts to change this directive during a
+    restart will be ignored, but MaxClients can be modified during
+    a restart.

+
+    
+
Special care must be taken when using this directive.  If
+    ServerLimit is set to a value much higher
+    than necessary, extra, unused shared memory will be allocated.  If
+    both ServerLimit and MaxClients are set to values
+    higher than the system can handle, Apache may not start or the
+    system may become unstable.

+
+    
+
With the prefork MPM, use this directive only
+    if you need to set MaxClients higher higher than 256.
+    Do not set the value of this directive any higher than what you
+    might want to set MaxClients to.

+
+    
+
With the worker MPM, use this directive only
+    if your MaxClients and
+    ThreadsPerChild
+    settings require more than 16 server processes.  Do not set the
+    value of this directive any higher than the number of server
+    processes required by what you may want for MaxClients  and ThreadsPerChild.

+
+
+

+

+StartServers Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Number of child server processes created at startup
Syntax:
+StartServers number
+
+
Default:StartServers 5
Context:server config
Status:MPM
Module:worker

+

+
+    
+
The StartServers directive sets the
+    number of child server processes created on startup. As the number
+    of processes is dynamically controlled depending on the load,
+    there is usually little reason to adjust this parameter.

+
+
+

+See also:
+

+
+

+

+StartThreads Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Nubmer of threads each child creates on startup
Syntax:
+StartThreads number
+
+
Default:StartThreads 5
Context:server config
Status:MPM
Module:perchild

+

+
+    
+
Number of threads each child creates on startup. As the
     number of threads is dynamically controlled depending on the
     load, there is usually little reason to adjust this
     parameter.

-    

-
-    
ThreadLimit

-
-    
Syntax: ThreadLimit
-    number

-     Default: ThreadLimit
-    64

-     Context: server config

-     Status: MPM

-     Module: worker

-
-    
This directive sets the maximum configured value for
-    ThreadsPerChild for 
-    the lifetime of the Apache process.  Any attempts to change this 
-    directive during a restart will be ignored, but 
-    ThreadsPerChild can be modified during a restart up to 
-    the value of this directive.

-
-    
Special care must be taken when using this directive.
-    If ThreadLimit is set to a value much higher than 
-    ThreadsPerChild, extra unused shared memory will be 
-    allocated.  If both ThreadLimit and 
-    ThreadsPerChild are set to values higher than the system 
-    can handle, Apache may not start or the system may become 
-    unstable.

-
-    
Use this directive only if you need to set 
-    ThreadsPerChild higher than 64.  Do not set the value of 
-    this directive any higher than what you might want to set 
-    ThreadsPerChild to.

-    

-
-    
ThreadsPerChild

-
-    
Syntax: ThreadsPerChild
-    number

-     Default: ThreadsPerChild
-    50

-     Context: server config

-     Status: MPM

-     Module: worker, mpm_winnt

-
-    
This directive sets the number of threads created by each
+
+
+

+

+ThreadLimit Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Sets the upper limit on the configurable number of threads
+per child process
Syntax:
+ThreadLimit number
+
+
Default:ThreadLimit 64
Context:server config
Status:MPM
Module:worker

+

+
+    
+
This directive sets the maximum configured value for ThreadsPerChild for the lifetime
+    of the Apache process.  Any attempts to change this directive
+    during a restart will be ignored, but ThreadsPerChild can be modified
+    during a restart up to the value of this directive.

+
+    
+
Special care must be taken when using this directive.  If
+    ThreadLimit is set to a value much higher
+    than ThreadsPerChild,
+    extra unused shared memory will be allocated.  If both
+    ThreadLimit and ThreadsPerChild are set to values
+    higher than the system can handle, Apache may not start or the
+    system may become unstable.

+
+    
+
Use this directive only if you need to set ThreadsPerChild higher than 64.  Do
+    not set the value of this directive any higher than what you might
+    want to set ThreadsPerChild to.

+
+
+

+

+ThreadsPerChild Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: Number of threads created by each child process
Syntax:
+ThreadsPerChild number
+
+
Default:ThreadsPerChild 50
Context:server config
Status:MPM
Module:worker, mpm_winnt

+

+
+    
+
This directive sets the number of threads created by each
     child process. The child creates these threads at startup and
     never creates more. if using an MPM like mpmt_winnt, where
     there is only one child process, this number should be high
@@ -698,67 +1167,109 @@
     like worker, where there are multiple child processes, the
     total number of threads should be high enough to handle the
     common load on the server.

-    

-
-    
User directive

-    
-
-    
Syntax: User
-    unix-userid

-     Default: User
-    #-1

-     Context: server config, virtual
-    host

-     Status: core

-     Module: worker, perchild,
-    prefork

-    The User directive sets the userid as which the server will
-    answer requests. In order to use this directive, the standalone
-    server must be run initially as root. Unix-userid is
-    one of: 
-
-    

-      
A username

-
-      
Refers to the given user by name.

-
-      
# followed by a user number.

-
-      
Refers to a user by their number.

-    

-    The user should have no privileges which result in it being
-    able to access files which are not intended to be visible to
-    the outside world, and similarly, the user should not be able
-    to execute code which is not meant for httpd requests. It is
-    recommended that you set up a new user and group specifically
-    for running the server. Some admins use user
-    nobody, but this is not always possible or
-    desirable. For example mod_proxy's cache, when enabled, must be
-    accessible to this user (see mod_proxy's CacheRoot
-    directive). 
-
-    
Notes: If you start the server as a non-root user, it will
+
+
+

+

+User Directive
+

+
+
+
+
+

+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Description: The userid under which the server will answer
+requests
Syntax:
+User unix-userid
+
+
Default:User #-1
Context:server config, virtual host
Status:MPM
Module:worker, perchild, prefork

+

+
+    
+
The User directive sets the userid as
+    which the server will answer requests. In order to use this
+    directive, the standalone server must be run initially as
+    root. Unix-userid is one of:

+
+    
+

+      
+
A username

+
+      
+
Refers to the given user by name.

+
+      
+
# followed by a user number.

+
+      
+
Refers to a user by their number.

+    
+

+
+    
+
The user should have no privileges which result in it being
+    able to access files which are not intended to be visible to the
+    outside world, and similarly, the user should not be able to
+    execute code which is not meant for httpd requests. It is
+    recommended that you set up a new user and group specifically for
+    running the server. Some admins use user nobody, but
+    this is not always possible or desirable. For example
+    mod_proxy's cache, when enabled, must be
+    accessible to this user (see CacheRoot).

+
+    
+
Notes: If you start the server as a non-root user, it will
     fail to change to the lesser privileged user, and will instead
     continue to run as that original user. If you do start the
     server as root, then it is normal for the parent process to
     remain running as root.

 
-    
Special note: Use of this directive in <VirtualHost>
-    is no longer supported. To configure your server for suexec use SuexecUserGroup.
-    SECURITY: Don't set User (or Group) to
-    root unless you know exactly what you are doing,
-    and what the dangers are.

-
-    

-    

-  
+    
+
Special note: Use of this directive in <VirtualHost> is no longer supported. To
+    configure your server for suexec use
+    SuexecUserGroup.

+
+
+

+
+
+
+
+

+

+Security
+
 
+
Don't set User
+(or Group) to
+root unless you know exactly what you are doing, and what
+the dangers are.

+

+

+
+
+

+
Apache HTTP Server Version 2.0

+IndexHome
+
+ - diff --git a/docs/manual/mod/prefork.html b/docs/manual/mod/prefork.html index ef147465cf..606c477e25 100644 --- a/docs/manual/mod/prefork.html +++ b/docs/manual/mod/prefork.html @@ -1,39 +1,49 @@ - - - - - - - Apache MPM prefork - - - - - - -

Multi-Processing Module prefork

- -

This Multi-Processing Module implements a non-threaded, - pre-forking web server.

- -

Status: MPM
- Source File: prefork.c
- Module Identifier: - mpm_prefork_module

- -

Summary

- -

This Multi-Processing Module (MPM) implements a + + + + +prefork - Apache HTTP Server + + + +

+
+[APACHE DOCUMENTATION]

Apache HTTP Server Version 2.0

+
+

Apache Module prefork

+ + + + +
+ + + + + + + + + + +
Description: +Implements a non-threaded, pre-forking web server +
Status:MPM
Module Identifier:mpm_prefork_module
+
+

Summary

+ + +

This Multi-Processing Module (MPM) implements a non-threaded, pre-forking web server which handles request in a manner very similar to the default behavior of Apache 1.3 on Unix.

-

A single control process is responsible for launching child + +

A single control process is responsible for launching child processes which listen for connections and serve them when they arrive. Apache always tries to maintain several spare or idle server processes, which stand ready to serve incoming @@ -41,193 +51,314 @@ child processes to be forked before their requests can be served.

-

The StartServers, MinSpareServers, - MaxSpareServers, and MaxClients - regulate how the parent process creates children to serve - requests. In general, Apache is very self-regulating, so most - sites do not need to adjust these directives from their default - values. Sites which need to serve more than 256 simultaneous - requests may need to increase MaxClients, while - sites with limited memory may need to decrease - MaxClients to keep the server from thrashing - (swapping memory to disk and back). More information about - tuning process creation is provided in the performance hints + +

The StartServers, + MinSpareServers, + MaxSpareServers, and + MaxClients regulate how + the parent process creates children to serve requests. In general, + Apache is very self-regulating, so most sites do not need to + adjust these directives from their default values. Sites which + need to serve more than 256 simultaneous requests may need to + increase MaxClients, + while sites with limited memory may need to decrease MaxClients to keep the server from + thrashing (swapping memory to disk and back). More information + about tuning process creation is provided in the performance hints documentation.

-

While the parent process is usually started as root under - Unix in order to bind to port 80, the child processes are - launched by Apache as a less-privileged user. The - User and Group directives are used to - set the privileges of the Apache child processes. The child - processes must be able to read all the content that will be - served, but should have as few privileges beyond that as - possible. In addition, unless suexec is used, these directives also - set the privileges which will be inherited by CGI scripts.

- -

MaxRequestsPerChild controls how frequently the - server recycles processes by killing old ones and launching new - ones.

- -

See also: Setting which addresses and - ports Apache uses.

- -

Directives

- - -
- -

AcceptMutex - Directive

- -

Syntax: AcceptMutex - default|method
- Default: AcceptMutex - default
- Context: server config
- Status: core

- -

The AcceptMutex directives sets the method that - Apache uses to serialize multiple children accepting requests - on network sockets. Prior to Apache 2.0, the method was + +

While the parent process is usually started as root under Unix + in order to bind to port 80, the child processes are launched by + Apache as a less-privileged user. The User and Group directives are used to set + the privileges of the Apache child processes. The child processes + must be able to read all the content that will be served, but + should have as few privileges beyond that as possible. In + addition, unless suexec is used, + these directives also set the privileges which will be inherited + by CGI scripts.

+ + +

+MaxRequestsPerChild + controls how frequently the server recycles processes by killing + old ones and launching new ones.

+ + +

+See also: +

+ +

Directives

+ +
+

+AcceptMutex Directive +

+ + + + +
+ + + + + + + + + + + + + + + + + + + +
Description: Method that Apache uses to serialize multiple children +accepting requests on network sockets
Syntax: +AcceptMutex default|method + +
Default:AcceptMutex default
Context:server config
Status:MPM
Module:prefork
+
+ + +

The AcceptMutex directives sets the + method that Apache uses to serialize multiple children accepting + requests on network sockets. Prior to Apache 2.0, the method was selectable only at compile time. The optimal method to use is - highly architecture and platform dependent. For further - details, see the performance - tuning documentation.

+ highly architecture and platform dependent. For further details, + see the performance tuning + documentation.

-

If this directive is set to default, then the + +

If this directive is set to default, then the compile-time selected default will be used. Other possible methods are listed below. Note that not all methods are available on all platforms. If a method is specified which is not available, a message will be written to the error log listing the available methods.

-
-
flock
- -
uses the flock(2) system call to lock the - file defined by the LockFile directive.
- -
fcntl
- -
uses the fnctl(2) system call to lock the - file defined by the LockFile directive.
- -
sysvsem
- -
uses SySV-style semaphores to implement the mutex.
- -
pthread
- -
uses POSIX mutexes as implemented by the POSIX Threads + +
+ +
+flock +
+ + +
uses the flock(2) system call to lock the + file defined by the LockFile directive.
+ + +
+fcntl +
+ + +
uses the fnctl(2) system call to lock the + file defined by the LockFile directive.
+ + +
+sysvsem +
+ + +
uses SySV-style semaphores to implement the mutex.
+ + +
+pthread +
+ + +
uses POSIX mutexes as implemented by the POSIX Threads (PThreads) specification.
-
-
- -

MaxSpareServers directive

- - Syntax: MaxSpareServers - number
- Default: MaxSpareServers - 10
- Context: server config
- Status: core - -

The MaxSpareServers directive sets the desired maximum - number of idle child server processes. An idle process - is one which is not handling a request. If there are more than - MaxSpareServers idle, then the parent process will kill off the - excess processes.

- -

Tuning of this parameter should only be necessary on very + +

+ + +
+

+MaxSpareServers Directive +

+ + + + +
+ + + + + + + + + + + + + + + + + + + +
Description: Maximum number of idle child server processes
Syntax: +MaxSpareServers number +
+ +
Default:MaxSpareServers 10
Context:server config
Status:MPM
Module:prefork
+
+ + +

The MaxSpareServers directive sets the + desired maximum number of idle child server processes. An + idle process is one which is not handling a request. If there are + more than MaxSpareServers idle, then the parent process will kill + off the excess processes.

+ + +

Tuning of this parameter should only be necessary on very busy sites. Setting this parameter to a large number is almost always a bad idea.

-

See also MinSpareServers and - StartServers.

-
- -

MinSpareServers directive

- - Syntax: MinSpareServers - number
- Default: MinSpareServers - 5
- Context: server config
- Status: core - -

The MinSpareServers directive sets the desired minimum - number of idle child server processes. An idle process - is one which is not handling a request. If there are fewer than - MinSpareServers idle, then the parent process creates new - children at a maximum rate of 1 per second.

- -

Tuning of this parameter should only be necessary on very + +

+See also: +

+ +
+

+MinSpareServers Directive +

+ + + + +
+ + + + + + + + + + + + + + + + + + + +
Description: Minimum number of idle child server processes
Syntax: +MinSpareServers number + +
Default:MinSpareServers 5
Context:server config
Status:MPM
Module:prefork
+
+ + +

The MinSpareServers directive sets the + desired minimum number of idle child server processes. An + idle process is one which is not handling a request. If there are + fewer than MinSpareServers idle, then the parent process creates + new children at a maximum rate of 1 per second.

+ + +

Tuning of this parameter should only be necessary on very busy sites. Setting this parameter to a large number is almost always a bad idea.

-

This directive has no effect on Microsoft Windows.

- -

See also MaxSpareServers and - StartServers. - -

- + +

This directive has no effect on Microsoft Windows.

+ + +

+See also: +

+ +
+

Apache HTTP Server Version 2.0

+IndexHome +
+ -